The SCID Mouse: Skin xenograft core utilizes severe combined immunodeficient (SCID) beige double mutant mice to host living of human skin (and skin-related cells) in the form of split thickness skin grafts or synthetic skin constructs. The three specific aims of the core are (1) to provide members of the YSDRC (both established and junior investigators, including investigators with YSDRC P/F projects) with limited numbers of C.B-17 SCID/beige mice engrafted with healthy adult human skin or skin constructs for use in a variety of skin disease-related studies, including feasibility studies; (2) to train members of the YSDRC to generate such mice once feasibility has been established; and (3) to develop variant models of this technique for new and novel applications, specifically focussing on synthetic skin equivalents constructed from distinct populations of cells, that in some cases may be genteically modified to alter biologic functions.